Tumours Prepare Sites Of Metastasis Formation

Tumours help prepare remote sites in the body for the formation of metastases, a study has found. The tumours send out proteins, which induce the target tissue to produce fibronectin, a protein outside cells that binds to receptors on various cells, including certain bone marrow cells that are progenitors of blood cells. The authors showed that in mice bearing tumours, these bone marrow cells enter the bloodstream to go to the future metastatic target tissue, where they form clusters to support and stabilize the tumour cells that arrive later.

What's more, the bone marrow cells are required for tumours to form metastases, at least in mice, David Lyden and colleagues report in the 08 Dec 2005 issue of Nature (Vol. 438, No. 7069, pp. 820-827). They also show that different tumour types generate different factors, which direct the bone marrow cells to different target tissues.

These findings suggest that inhibiting the process whereby the tumour prepares future metastatic sites could keep metastases from spreading in cancer patients.

"Inhibitors of the pathway would be of tremendous interest for possibly blocking metastasis," writes Patricia S. Steeg in an accompanying News and Views article.